60秒科学:青春期, 孩子会变笨？

在《科学》杂志上的一篇研究中，研究者们描述了青春期时人体内细胞和分子的改变，正是这种改变促使这段时期的人们智力水平低下。

Ah, puberty. A time for raging hormones², growing independence and being stupid. Okay, not every teenager gets stupid. But they actually do learn less. And in a study published in the journal Science , researchers describe the cellular³ and molecular⁴ changes that drive this puberty-associated desmartification.

Learning happens in the hippocampus, a brain region that plays a key role in acquiring memories. From a cellular perspective, learning takes place when the connections between nerve cells are strengthened. Interfere⁵ with those stronger neuronal connections, and a brain can have trouble laying down new memories. Which, apparently⁶, is what happens in adolescence⁷. At least in mice.

Scientists used a variety of methods to study the brains of pubescent female mice. And they discovered that a particular protein, a kind of GABA receptor, for those of you keeping score at home, crops up in the hippocampus during puberty. These receptor proteins interfere with neuron communication and thus prevent the sort of synaptic strengthening these young animals need to learn.

The good news: a hormone¹ that quiets this pubescent protein turns these young animals back into better learners again. Imagine, a hormone that actually makes an adolescent act smarter.

—Karen Hopkin

啊，青春期！一个荷尔蒙串升的时期，一个增强独立性和变笨的时期。另担心，当然不是每个青少年都会变笨。但是他们确实在那个时期降低了认知水平。并且，在《科学》杂志上的一篇研究中，研究者们描述了青春期时人体内细胞和分子的改变，正是这种改变促使这段时期的人们智力水平低下。

认知开始于海马体，它是大脑中的一个区域，对人类获取知识有着十分重要的作用。从细胞的角度来说，当神经细胞之间的连接加强时，认知便开始了。如果阻断这些强烈的连接，大脑就不能记忆新知识了。很明显，青春期正是有着这样的现象。至少在老鼠中极为普遍。

科学家们使用了许多方法来研究思春期雌性鼠类的大脑。他们意外地在处于青春期的海马体中发现了一种特殊的蛋白质，它是一种GABA （伽马氨基丁酸）受体（正是它让一些青少年在家里不敢说出自己的真实成绩）。这些受体蛋白质会干扰神经元之间的连接，从而阻碍染色体提高年青动物的认知能力。

令人欣慰的是，荷尔蒙会减轻这种蛋白质的作用，从而让这些年青的动物回到更好的学习状态。这么说，荷尔蒙事实上会让青少年更加聪明哦！
 

1 hormone   

n.荷尔蒙，激素，内分泌

参考例句：

• Hormone implants are used as growth boosters.激素植入物被用作生长辅助剂。
• This hormone interacts closely with other hormones in the body.这种荷尔蒙与体內其他荷尔蒙紧密地相互作用。

2 hormones   

n. 荷尔蒙，激素 名词hormone的复数形式

参考例句：

• This hormone interacts closely with other hormones in the body. 这种荷尔蒙与体內其他荷尔蒙紧密地相互作用。
• The adrenals produce a large per cent of a man's sex hormones. 肾上腺分泌人体的大部分性激素。

3 cellular   

adj.移动的；细胞的，由细胞组成的

参考例句：

• She has a cellular telephone in her car.她的汽车里有一部无线通讯电话机。
• Many people use cellular materials as sensitive elements in hygrometers.很多人用蜂窝状的材料作为测量温度的传感元件。

4 molecular   

adj.分子的；克分子的

参考例句：

• The research will provide direct insight into molecular mechanisms.这项研究将使人能够直接地了解分子的机理。
• For the pressure to become zero, molecular bombardment must cease.当压强趋近于零时，分子的碰撞就停止了。

5 interfere   

v.(in)干涉，干预；(with)妨碍，打扰

参考例句：

• If we interfere, it may do more harm than good.如果我们干预的话，可能弊多利少。
• When others interfere in the affair,it always makes troubles. 别人一卷入这一事件，棘手的事情就来了。

6 apparently   

adv.显然地；表面上，似乎

参考例句：

• An apparently blind alley leads suddenly into an open space.山穷水尽，豁然开朗。
• He was apparently much surprised at the news.他对那个消息显然感到十分惊异。

7 adolescence   

n.青春期，青少年

参考例句：

• Adolescence is the process of going from childhood to maturity.青春期是从少年到成年的过渡期。
• The film is about the trials and tribulations of adolescence.这部电影讲述了青春期的麻烦和苦恼。